(Reuters Health) - With the Trump
Administration threatening to loosen air pollution controls, a new study
is showing that even existing rules are causing tens of thousands of
extra deaths in the United States each year.

Researchers used 12 years of data - health records from nearly 61
million Medicare beneficiaries, combined with a massive databank of
pollution readings - to link specific air quality levels to death
rates.

They found that for every increase of just 10 micrograms in
small-particle pollution known as PM2.5, the death rate went up 7.3
percent. That's the equivalent of 120,000 fatalities among people
age 65 and older, lead author Qian Di of the Harvard T.H. Chan
School of Public Health in Boston told Reuters Health in a telephone
interview.

For every 10 part-per-billion rise in ozone concentration, the
mortality rate rose by 1.1 percent, producing an extra 19,000 deaths
just among the elderly.

Even in years when the concentrations in a region were low, "we
continued to see significant associations between exposure and
mortality," Di and his colleagues write in the New England Journal
of Medicine.

Their conclusion: current U.S. rules are not strict enough to
prevent pollution-related deaths and further reductions in pollution
will produce a big drop in fatalities.

"It is clear from this study that there is not really a safe level
of air pollution," said Dr. Brian W. Christman, vice chair of the
department of medicine at Vanderbilt University Medical Center in
Nashville, Tennessee, who was not involved in the research.

"The Clean Air Act and the Environmental Protection Agency have done
great work, but the data indicates that additional effort to reduce
PM2.5 and ozone would save lives," Christman, who is also a
spokesman for the American Lung Association, told Reuters Health by
phone. "As a matter of fact, further reduction in PM2.5 below the
(federal standard) of 12 micrograms per cubic meter are likely to be
even more effective than previous reductions."

Senior study author Francesca Dominici, a professor of biostatistics
at Harvard, told Reuters Health in a telephone interview that she
hoped the findings "will change the course of recent discussions
about dismantling EPA and EPA research and leaving the Paris
agreement" designed to slow global climate change by reducing
pollution levels.

The results come at a time when the Trump administration has begun
"to dismantle guidelines intended to reduce emissions from
coal-fired electricity plants" and may revoke the waiver that
allowed California to adopt stricter vehicle emission standards,
according to an editorial accompanying the study.

"Revoking this waiver could have the effect of exposing more than
100 million Americans to higher levels of automobile emissions," the
Journal warns. "Trumpís proposed budget includes crippling cuts to
the EPA, including cuts in funding for both federal and state
enforcement of regulations. The increased air pollution that would
result from loosening current restrictions would have devastating
effects on public health."

The particles studied are dangerous because their tiny size - only
visible with an electron microscope - allows them to get deep into
the lungs to do damage, and from there they can also enter the
bloodstream. According to the Environmental Protection Agency, from
2000 to 2015 the average concentration of PM 2.5 pollution
nationally has declined by 37 percent thanks to stricter air
standards.

According to the new study, the two regions that saw the greatest
improvements in air quality were the central and southeastern United
States.

Satellite and weather data, computer models and data from 1,928
particle monitoring stations and 1,877 ozone modeling stations were
used to estimate exposure over each square kilometer of the country.

The task was so massive the number crunching had to be done by
supercomputer over Harvard's Christmas break, Di noted.

Because the database was so large, Di and his colleagues were also
able to determine that subgroups, including men, blacks, Asians,
Hispanics and people eligible for the Medicaid health plan for the
poor faced the highest risk from small particle pollution.

It shows "this is not just a health issue, but a social equality
issue as well," said Di, a doctoral student in Harvard's department
of environmental health.